(a) Field of the Invention
This invention relates to a dental hygienic device, and, more particularly, it is concerned with a device for positively and effectively scaling and washing-out sordes (including dental calculus or tartars) on the surface of teeth at a portion which is a so-called "gum pocket" or "cul-de-sac" between a tooth and a gingival edge, and also for removing various germs (in particular, aerophobic bacteria) which are ever present in the gum pocket as well, as the consequence of which the pathological condition of the soft tissues of the teeth including the gum pocket is improved and formation of sordes and sedimentation of tartars on the surface of teeth are also suppressed, such improved conditions being able to be constantly maintained.
(b) Description of Prior Art
The sordes and tartars on the surface of teeth at the gum pocket tend to cause dental diseases such as pyorrhea alveolaris (or gum disease), etc. In view of considerably strong adhesive force of the sordes and tartars onto the surface of teeth, it is fairly difficult to remove them with a tooth brush. From the clinical standpoint of the dental surgery, it has been and is usually a practice to remove the dental calculus on the surface of teeth by inserting the tip end of a scaler into the gum pocket to scrape them off, or removing the sordes and tartars by impinging a jet stream of water onto the gum pocket through a jet nozzle for washing the oral cavity to peel them off.
However, the scraping of the tartars and sordes with use of a blade hand-piece would stimulate the dental nerves to arouse pain and disagreeableness on the treated part, or it tends to scratch the gingiva to provoke bleeding, with the further disadvantage of an inefficient and time-taking operation. Moreover, such a scaling operation cannot be controlled by a patient himself (or herself).
The removal by scraping of tartars and sordes with the use of a jet water nozzle is to remove them on the surface of teeth by directly impinging the pressurized jet water onto the surface of teeth at the gum pocket. For this purpose, it is necessary that the gingiva b at the gum pocket where the jet water is impinged be sufficiently separated from the surface of teeth a to be brought to an open state, as indicated by a double dots-and-dash line in FIG. 5 of the accompanying drawing, whereby the surface of teeth becomes exposed to the outside to enable the jet water to directly act on the sordes and tartars on the surface of the teeth. In practice, however, the gingiva b at the gum pocket does not become sufficiently separated from the surface of the tooth a to be brought to an open state, even when the jet water at a considerably high ejecting pressure is impinged on the gum pocket, hence the jet water is difficult to act effectively on the surface of the teeth at the gum pocket, where the sordes and tartars are adhered.
As the ejecting pressure of the jet water is increased to sufficiently open the gingiva b, impingement of the jet water stream to the surface of teeth a, the gingiva b, and every other part of the mouth becomes excessive to result in injury to the teeth a and the gingiva b, or causing pain and disagreeable feeling to the user. In addition, since a large quantity of water flows out of the mouth during use of the jet water nozzle, it compels the user to lean his or her body forward, approaching his or her face closer to the wash basin, etc. to handle the jet nozzle hand-piece in a very confined, slouched posture.